That really helps. Thanks very much! I also checked personal pages of PHD students listed in Brown CS department website, and I found that the proportion of PHD students who were Master students in Brown before is indeed relatively high.
I still have another doubt. As I have received master admissions from Brown and UPenn (the program in UPenn is Robotics), I need to make a decision between them soon. I'm interested in computer vision and my major concern now is that the size of CV group in Brown is relatively smaller than that of UPenn. For a PHD student, how do you think of the importance of research group size he is in? Besides, do you have any opinions about these two programs?
Thanks for your time again!